int exported;
static int hidden = 3;

static int hidden_function(int x)
{ /* ... */
}

void globally_known(int y)
{ /* ... */
  hidden_function(y+1);
}

/* file string_set.c */
#include <string.h>

#define MAX_TRACKED_INCLUDES 1000
#define MAX_PATHNAME_LENGTH 500

static char already_included
		   [MAX_TRACKED_INCLUDES]
		   [MAX_PATHNAME_LENGTH];
static int num_tracked = 0;

/* rep invariant:
    no duplicates in already_included */

void string_set_insert(char [])
  /* effect: put a copy of s in the set */
{
   /* ... */
}

int string_set_has(char [])
   /* effect: is s in the set? */
{
   /* ... */
}